Long term memories are formed when our brain creates a network of neurons that all fire together in a consistent sequence. It has long been thought that once this network is formed we are able to gaze upon the memory, but it is essentially read-only. We are not manipulating the construction of the network, and therefore unable to change the memory after it is formed. This is how we would presumably want it to work. Sure, memories can fade and certain details can be lost over time, but we don't go in and change components of the memory just by calling it up in our brains.
A neuroscientist had a theory that memory is malleable, and has been able to demonstrate it through experimentation. He is basically saying that when we access a memory we also risk altering that memory by inadvertently weaving in elements or changing details based on other related memories or a multitude of external factors. Once we are done thinking about it and want to commit that thing back to memory, it is forever changed and our initial copy is gone. We have no conscious way to know the memory changed because in our head the neurons that “held” that memory have essentially been re-wired. We will be just as confident, if not more1 confident, of the new incorrect memory as we were of the old one.
This memory manipulation especially affects “flash bulb” memories. This is when you say things like, “I will never forget exactly what I was doing the moment I learned about the September 11th attacks”. As we access the memory it gets changed, but our confidence in the accuracy of that memory only gets stronger.
"Nader, now a neuroscientist at McGill University in Montreal, says his memory of the World Trade Center attack has played a few tricks on him. He recalled seeing television footage on September 11 of the first plane hitting the north tower of the World Trade Center. But he was surprised to learn that such footage aired for the first time the following day. Apparently he wasn’t alone: a 2003 study of 569 college students found that 73 percent shared this misperception."Basically… a lot of our memories are false. Our brain is continuously manipulating them as we access them.
This is a scary thought. To a certain extent the way we perceive our own self is made up of false information. We are making decisions based on incorrect facts that we think are true. Most of our conversations involve recounting stories from our past. Most of this stuff is filled with lies that we don't realize we are telling.
However, it may not be all bad. There might be a reason for why things work this way. We might be changing our memories for our own good.
“…editing might be another way to learn from experience. If fond memories of an early love weren't tempered by the knowledge of a disastrous breakup, or if recollections of difficult times weren't offset by knowledge that things worked out in the end, we might not reap the benefits of these hard-earned life lessons. Perhaps it’s better if we can rewrite our memories every time we recall them. Nader suggests that reconsolidation may be the brain’s mechanism for recasting old memories in the light of everything that has happened since. In other words, it just might be what keeps us from living in the past.”This article is worth a read.
➔ How Our Brains Make Memories | Science & Nature | Smithsonian Magazine
- Because we have just recalled this memory it will feel fresher in our mind and we will believe that we successfully extracted every detail, when in actuality we have only further obscured the truth. ↩
